Defibrillator battery charger

Abstract

Battery charger having means for delivering a trickle charge to maintain a difibrillator battery in a normally charged condition, switch actuated means for delivering a fast charge current to the battery, and means responsive to the battery voltage for supplying operating power to the defibrillator in the event that the battery voltage falls below a predetermined level whereby the charger will power the difibrillator directly in the event that the battery is unable to do so. The battery and defibrillator are protected from damage due to overcharging of the battery by interrupting the charging current in the event that the temperature of the battery exceeds a predetermined level or the voltage applied to the defibrillator reaches a predetermined level.

I claim: 
     
       1. In combination, a defibrillator, a battery connected to the defibrillator for supplying operating power thereto, and a charger connected to the battery, said charger comprising: means for delivering a trickle charge current to the battery, means for delivering a fast charge current to the battery for charging the same at a rate faster than the trickle charge, and means responsive to the level of the battery voltage for supplying operating power directly from the charger to the defibrillator in the event that the battery voltage falls below a predetermined level. 
     
     
       2. The combination of claim 1 wherein the battery charger includes means responsive to the temperature of battery for interrupting the fast charge current when the temperature reaches a predetermined level. 
     
     
       3. The combination of claim 1 wherein the battery charger includes means responsive to the battery voltage for interrupting the fast charge current in the event that said voltage reaches a predetermined level. 
     
     
       4. The combination of claim 1 wherein the battery charger includes means for providing a visual indication in the event that the battery voltage drops below a predetermined level. 
     
     
       5. In combination, a defibrillator, a battery connected to the defibrillator for supplying operating power thereto, and a battery charger connected to the battery, said battery charger comprising: a power supply, means for delivering a trickle charge current from the power supply to the battery for maintaining the same in a charged condition, means for providing a control signal having a normal level and a fast charge level, and means responsive to the control signal and to the level of the battery voltage for applying a fast charge current of greater magnitude than the trickle charge current to the battery when the control signal is at the fast charge level and for delivering operating power directly from the power supply to the defibrillator in the event that the battery voltage drops to a predetermined level relative to the normal level of the control signal. 
     
     
       6. The combination of claim 5 wherein the means for applying the fast charge current and delivering operating power comprises a silicon controlled rectifier (SCR). 
     
     
       7. The combination of claim 6 wherein the anode and cathode of the SCR are connected respectively to the power supply and one terminal of the battery and wherein the control signal is applied to the gate of the SCR. 
     
     
       8. The combination of claim 5 further including means responsive to the battery voltage for returning the control signal from the fast charge level to the normal level in the event that the battery voltage reaches a predetermined level. 
     
     
       9. In a battery charger for use with a battery powered defibrillator: a power supply, output terminals for connection to the terminals of a battery connected to the defibrillator, means for delivering a charging current from the power supply to the output terminals for maintaining the battery in a charged condition, switching means including a silicon controlled rectifier (SCR) connected between the power supply and the output terminals for delivering operating current for the defibrillator directly from the power supply to the output terminals, an amplifier, means for applying a reference signal to one input of the amplifier, means including a manually operable switch for applying an input signal to a second input of the amplifier whereby the amplifier has a first output level when the switch is in a first position and a second output level when the switch is in a second position, and a transistor connected between the output of the amplifier and the gate of the SCR whereby the level of the signal applied to the gate of SCR corresponds to the output level of the amplifier, the SCR being actuated when the amplifier output is at the second level. 
     
     
       10. The battery charger of claim 9 further including means responsive to the temperature of the battery for applying an input signal to the second input of the amplifier to return the amplifier output to the first level in the event that the battery temperature exceeds a predetermined level.